Physical, chemical and mechanical aspects of the durability of (semicrystalline) thermoplastics

The term durability designates the capacity of a material to withstand for extended periods of time (aggressive) environmental action. Depending on the intended use of a material, durability can be expressed in terms of time to failure, creep deformation or residual strength or discoloration. In all cases it is highly desirable to know the mechanisms involved in ageing and their kinetics. In this presentation we discuss the mechanical behaviour of stabilised and aged polypropylene. Using different methods of characterisation we try to identify the physical mechanisms occurring during ageing (chain scission, recristallisation)